1. Field of the Invention
The present invention relates to a battery charging system for miniature hearing aid devices having an internal rechargeable battery and more particularly to a system which provides positive indication to the user that the battery is charging.
2. Description of the Prior Art
Rapid advancements have been made in the hearing aid technology with the advent of microelectronic circuits. For example, it is now possible to provide a hearing aid in the form of a molded plug which will fit in the ear of the user and which contains an integrated circuit amplifier, input and output transducers, a volume control and switch, and a rechargeable battery. However, due to the requirement for very small size, the batteries such as are now in common use have a small energy storage capacity and therefore must frequently be recharged. In known prior art hearing aids of the self-contained type, it is common to have extremely small, receptacle-type contacts embedded in the device. At night or at other times when the hearing aid is not in use, the user plugs a cable from a battery charger into such contacts for recharging of the battery. Due to the small sizes required for such connectors and the frequent use thereof, many problems are experienced from wear and breakage of the contacts, poor connections, and similar mechanical type problems. Another factor which makes such charging system somewhat unsatisfactory is that many wearers of hearing aids are elderly and have poor eyesight. This leads to difficulties for such users in making the necessary connection and to inadvertent damage during attempts to plug in the battery charger.
The present invention overcomes such problems and difficulties experienced with prior art battery charging systems for small, self-contained hearing aid devices.